| Official Name: | Khlung |
| Native Name: | ขลุง |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Chanthaburi |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Khlung |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 55044 |
| Population As Of: | 2005 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 22110 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 2202 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 12.4547°N 102.2214°W |
Khlung (Thai: ขลุง, in Thai pronounced as /kʰlǔŋ/) is the southernmost district (amphoe) of Chanthaburi province, eastern Thailand.
Neighboring districts are (from the northwest clockwise) Laem Sing, Mueang Chanthaburi, Makham, Pong Nam Ron of Chanthaburi Province, Bo Rai, Khao Saming, and Laem Ngop of Trat province. To the southeast is the Gulf of Thailand.
The district is divided into 12 sub-districts (tambons), which are further subdivided into 90 villages (mubans). Khlung is a town (thesaban mueang) which covers tambon Khlung. There are a further 11 tambon administrative organizations (TAO).
| No. | Name | Thai name | Villages | Pop. | ||
|---|---|---|---|---|---|---|
| 1. | Khlung | ขลุง | - | 11,259 | ||
| 2. | Bo | บ่อ | 10 | 6,715 | ||
| 3. | Kwian Hak | เกวียนหัก | 10 | 4,400 | ||
| 4. | Tapon | ตะปอน | 6 | 3,274 | ||
| 5. | Bang Chan | บางชัน | 6 | 3,735 | ||
| 6. | Wan Yao | วันยาว | 8 | 5,346 | ||
| 7. | Sueng | ซึ้ง | 11 | 4,830 | ||
| 8. | Map Phai | มาบไพ | 6 | 2,350 | ||
| 9. | Wang Sappharot | วังสรรพรส | 9 | 2,859 | ||
| 10. | Trok Nong | ตรอกนอง | 6 | 2,358 | ||
| 11. | Tok Phrom | ตกพรม | 11 | 3,844 | ||
| 12. | Bo Wen | บ่อเวฬุ | 7 | 4,074 |